Badgeman

Not very often, 1 mobilisation in 5 years is a reasonable generalisation barring any large shifts in current geopolitics.

You can ask to defer a mobilisation if you feel the timing would be too distributive for your career, marriage, children etc.

'Alongside the regulars' might be the wrong way to think about deployments, if you're mobilised it will be for your specialism/branch (several of which are land based), not plonked onto a random war canoe to fill out numbers.

You can't be mobilised until you're at trained strength, which takes minimum 2 years depending on your time commitment and the speed your unit gets you down for confirmation.

There will be volunteer mobilisation opportunities of varying length constantly available.

2.

You can attest after completing the recruitment test.

What your unit does with you while you wait for medical, PJFT and security clearance is up to them.

Midshipman

Lantern Swinger

Also worth pointing out that the RNR practice "intelligent mobilisation", and remember the aphorism "a volunteer is worth 10 pressed men". In other words we try to take people who are wanting to mobilise, whose employer is likely to be reasonably supportive - that cuts down on appeals and is in the interest of everyone.

That isn't to say that in the future a situation will arise where mass mobilisations are necessary. Different specialisations have different likelihoods of mobilisation as well - those with "enduring commitments" for instance.

So unless your wife is the one wanting you out of the house that might hopefully be of use. You should view it as a case of "when, not if", but hopefully at a point that is well suited to the rest of your life.

War Hero

At the height of Iraq/Afghan ops, some branches were mobilising the "willing" one year in every 4, and the "less willing" one year in every 5-7 (which actually meant only once). The "unwilling" were weeded out and sent packing back to civvie street.
Times have now changed, and depending on your chosen branch, you might well NOT get mobilised, however, things can change, and you need to be aware that "tomorrow" mobilisations may be back at a higher tempo. BUT, and a very big BUT, there are not only laws stating the maximum mobilisation period, but with the expansion of reserves, a strong desire to keep employers on-side, so a sensible planning assumption will be, that you could be mobilised once in each rate, but only if you pushed for it, it would normally be once in your career - BUT that is an ASSUMPTION!!!!